With my previous Vigor routers I used the console commands "ip route default wan1/wan2/off" to send all outward traffic through one particular WAN while the other WAN was always on for incoming connections but was only used in failover for outgoing sessions. I find those commands have been deleted in the 2952 and ask how to achieve the same result with the newer command set? Thanks.

Not sure, but the 2952 is still DrayOS so it may be the facility is still/only available in the GUI (I don't have a V2952 to check). otherwise, ask support.

To achieve that with current router models, you can now use the [Load Balance / Route Policy] rules to have all outbound traffic go over one WAN interface except when failing over - with route policy, you can also control the failover & failback (session handling on WAN reconnection) options.

Here's a guide on how to configure that:
Policy Routing with Metrics - Load Balancing, Address Mapping and VPN Routing

Thanks for the pointer to the configuration guide. I'll try out some test settings to see if I can get the behaviour I want.